1. Field of the Invention
The present invention is directed to enzymatically blocked-deesterified pectins that display pseudoplasticity and substantially no phase separation in an aqueous solution comprising at least one polyvalent cation, and processes for producing the same. In particular, the present invention is directed to enzymatically blocked-deesterified pectins prepared by deesterifying isolated high methoxyl pectins with enzymes. The present invention is also directed to processes for suspending particulates using enzymatically blocked-deesterified pectins prepared by deesterifying isolated high methoxyl pectins with enzymes. Furthermore, the present invention relates to stabilized aqueous systems containing enzymatically blocked-deesterified pectins prepared by deesterifying isolated high methoxyl pectins with enzymes.
2. Background of the Invention and Related Art
The problem encountered with drinks containing insoluble components, such as pulps, essential oils, and the like, is the tendency of the insoluble components to separate, e.g., via sedimentation or creaming.
In order to maintain insoluble components in suspension, xanthan has been added to fruity drinks to raise the viscosity or alter the rheology of the drink. Xanthan, when added to aqueous solutions even at low concentrations, exhibits very strong pseudoplasticity and viscoplasticity at low concentration without any evidence of thixotropy. However, xanthan adds negative organoleptic perception (undesirable mouth-feel) in beverages. Thus, there is a need to provide a suspension aid that has the desired properties of xanthan without the undesired mouth-feel.
Alginates and pectins have been used in beverages to raise viscosity since they do not add negative mouth feel. Alginates and pectins useful for this application, however, tend to undergo syneresis during long term storage. Attempts have been made to use pectins as suspension aids with reduced syneresis properties, but without success.
Pectin is a structural polysaccharide commonly found in the form of protopectin in plant cells. The backbone of pectin comprises xe2x88x9d-1-4 linked galacturonic acid residues which are interrupted with a small number of 1,2 linkedxe2x88x9d-L-rhamnose units. Some of the carboxyl groups of the galacturonic residues are esterified, typically by methyl groups. The remaining residues are present as free carboxyl groups. Esterification of the carboxyl groups occurs in the plant tissue after polymerization of the galacturonic acid residues. However, it is extremely rare for all of the carboxyl groups to be esterified. Usually, the degree of esterification varies from 0 to 90% of the available carboxylic groups.
The term xe2x80x9cdegree of esterificationxe2x80x9d is intended to mean the extent to which free carboxylic acid groups contained in the polygalacturonic acid chain of the pectin have been esterified (e.g., by methylation) or in other ways rendered non-acidic (e.g., by amidation).
Pectin is available as either low methoxyl pectin (LMP) or high methoxyl pectin (HMP). Low methoxyl pectin as defined here has a degree of esterification (DE) of less than about 45% and is highly reactive with cations such as calcium. High methoxyl pectin as defined here has a DE of greater than about 45% and typically is less reactive with polyvalent cations such as calcium.
The structure of the pectin, in particular the degree of esterification, dictates many of its physical and/or chemical properties. For example, pectin gelation caused by the presence of calcium cations depends especially on the degree of esterification. Gelation is believed to result from the calcium ions forming cross-linked complexes with free carboxyl groups of a number of pectin chains causing the formation of a continuous three-dimensional gelled matrix.
Pectin, as first extracted, has a relatively high degree of esterification of about 70-75%. Such pectin is ideal for use in jam and jellies. However, other uses require the preparation of pectins with different setting characteristics. This can be accomplished by modifying pectin to reduce the degree of esterification. One common process for achieving this is an acid hydrolysis. Alternative processes are directed to the use of alkali at low temperatures, ammonia, or to use a pectin methyl esterase.
During deesterification, the ester groups on the pectin can be removed in a random or blockwise manner. When the ester groups are removed from any galacturonic acid residues on more than one of the pectin chains non-sequentially, they are referred to as being deesterified in a xe2x80x9crandom manner.xe2x80x9d When the ester groups are removed either at non-reducing ends or next to free carboxyl groups by a single-chain mechanism in a sequential manner, they are referred to as being deesterified in a xe2x80x9cblockwise manner,xe2x80x9d as blocks of unesterified galacturonic acid units are created. The sequential or blockwise removal esters are typically mediated by pectin methyl esterases. The unesterified galacturonic acid units formed by blockwise deesterification are highly reactive to polyvalent cations such as calcium. Pectins having such blocks of unesterified galacturonic acid are said to be xe2x80x9ccalcium sensitive.xe2x80x9d
It is well known that the methyl content of pectin is modified in nature by plant pectin esterases that are present in the plant tissue. Many of these plant esterases, usually called pectin methyl esterases (PMEs), demethylate esterified carboxylic groups that are next to at least two contiguous free carboxylic acid groups. The demethylation proceeds in this way forming blocks. For example, the unpurified proteases papain and bromelain from plant tissue are also known to contain pectin methyl esterases as contaminants that demethylate pectins in a blockwise manner.
To a small extent these blocks of unesterified galacturonic acid units occur naturally in commercial high DE pectins when first isolated. In a commercial, pectin having a typical degree of esterification of approximately 68-74%, the length of the free carboxylic blocks may vary from molecule to molecule, and each pectin molecule typically includes several blocks of different lengths. For example, it is known that the distribution of the free carboxyl groups along the polymer chain is important for determining whether the pectin is suitable for use as a stabilizer for acidified milk drinks. It has been proposed that pectin can stabilize a suspension of casein particles by adsorbing onto the surface of the casein particles at specific points of the pectin molecule where the block-deesterified regions occur. To obtain complete stability a significant proportion of the surface of a casein particle should be covered by the pectin. Nevertheless, aside from stabilizing casein these pectins have found limited utility for stabilization of pulp or other materials in typical beverage applications.
Pectins that have been randomly deesterified have also been tested for use in stabilization of particles in liquid foods and beverages. Commercial pectins that have been reduced randomly to low-methoxyl pectins can also be reactive with polyvalent cations such as calcium. Calcium is the most common source of polyvalent cations for food gel applications involving these types of pectins. Gelation is due to the formations of intermolecular junction zones between homogalacturonic acid units. Because of the electrostatic nature of the bonds, pectin gels are very sensitive to conditions that can modify the environment of the carboxyl groups through which the calcium ion is linked to a neighboring pectin molecule. The gel forming ability of pectin increases with decreasing DE, and low methoxyl pectins with a large number of free carboxyl groups are very sensitive to low calcium levels. As the number of free carboxyl groups along the pectin backbone the increasing sensitivity of low DE pectin to calcium is an increased tendency for the pectin to gel and to display syneresis. The properties of gel contraction and syneresis in these types of randomly deesterified pectins are unsuitable for stabilization of particles in liquid foods and beverages.
Other, attempts have been made in the industry to use pectin as a suspending aid. For example, U.S. Pat. No. 5,866,190 issued to Barey discloses compositions for stabilizing a non-milk drink containing insoluble components comprising a pectin and alginate. The pectin of Barey can be amidated or non-amidated HMPs and LMPs. These compositions however display syneresis that is undesirable for this application. It is also essential that the pectin/alginate mixture be dissolved in an aqueous medium in the absence of free calcium ions or that a calcium complexing agent be used. The complexing agent is added either to the pectin/alginate solution or to the fruit juice.
WO 97/03574 from Christensen relates to a process for stabilizing proteins in an acidic environment with a high-ester pectin prepared by a recombinant DNA technique. The high-ester pectin of Christensen has a degree of esterification of about 70 to 80%. However, the high-ester pectin of Christensen is not pseudoplastic in aqueous solution at low concentrations and is of limited value as a suspension aid.
In view of the above, there is an existing need for a pectin suspension aid that has shear thinning behavior for use in aqueous food, cosmetic, and pharmaceutical products.
There is also an existing need for a pectin to produce a stable aqueous system with shear thinning behavior (pseudoplasticity) and acceptable mouth-feel for use as a particle suspending aid. Pseudoplasticity is a Theological behavior most desired for stabilization of particles in aqueous solution. An aqueous solution is characterized as being pseudoplastic if it displays decreasing viscosity with increasing shear rate. A xe2x80x9cstable aqueous systemxe2x80x9d refers to an aqueous system that can maintain stable viscosity without the formation of gels or without phase separation and syneresis. xe2x80x9cStable viscosityxe2x80x9d or xe2x80x9cstabilityxe2x80x9d refers to the maintenance of the insoluble components in suspension and the homogeneity of the suspension initially formed. Rheologically, the pseudoplasticity of the aqueous system is stable for a time period of at least one to twelve months or longer.
In addition, there is also an existing need for a pectin that does not undergo syneresis upon storage or form a separate gel phase even in the presence of relatively high levels of calcium such as 500 mM.
In view of the foregoing, one aspect of the invention is directed to enzymatically blocked-deesterified pectins that display pseudoplasticity and substantially no gel-contraction in aqueous solutions comprising at least one polyvalent cation, and processes for producing the same. In particular, the present invention is directed to enzymatically blocked-deesterified pectins prepared by deesterifying isolated high methoxyl pectins with enzymes.
The enzymatically blocked-deesterified pectin of the present invention preferably has a degree of esterification from about 45 to 65%, and more preferably from about 55 to 59%.
The enzymatically blocked-deesterified pectin of the present invention preferably has a calcium sensitivity greater than about 200 cP or a calcium fraction greater than 20, and a xcex94 degree of esterification from about 5 to 25%, and more preferably from about 8 to 15%.
The enzymatically blocked-deesterified pectin of the present invention is preferably prepared by treating isolated high methoxyl pectin with enzyme. The enzyme is extracted from plant tissues selected from at least one of apples, apricots, avocados, bananas, berries, limes, grapefruits, mandarins, cherries, currants, grapes, mangos, papayas, passion fruits, peaches, pears, plums, beans, carrots, cauliflowers, cucumbers, leeks, onions, peas, potatoes, radishes and tomatoes, preferably papain.
The enzymatically blocked-deesterified pectin preferably has a degree of esterification from about 45 to 65% when the degree of esterification of the isolated high methoxyl pectin is from about 68 to 72%, and more preferably a degree of esterification from about 55 to 59% when the degree of esterification of the isolated high methoxyl pectin is from about 68 to 72%. The isolated high methoxyl pectin preferably has a degree of esterification greater than about 60%, and more preferably greater than about 67%. The isolated high methoxyl pectin is preferably in an aqueous form or powder form.
The isolated high methoxyl pectin is preferably obtained from at least one of citrus peels, apple juices, apple ciders, apple pomade, sugar beets, sunflower heads, vegetables or waste products from plants selected from at least one of apples, sugar beet, sunflower and citrus fruits, and more preferably from at least one of limes, lemons, grapefruits, tangerines and oranges.
The enzymatically blocked-deesterified pectin of is preferably prepared by treating the isolated high methoxyl pectin with an enzyme, wherein the enzyme is extracted from plant tissues selected from at least one of apples, apricots, avocados, bananas, berries, limes, grapefruits, mandarins, cherries, currants, grapes, mangos, papayas, passion fruits, peaches, pears, plums, beans, carrots, cauliflowers, cucumbers, leeks, onions, peas, potatoes, radishes and tomatoes.
In addition, the present invention is also directed to processes for suspending insoluble particles which comprises adding enzymatically blocked-deesterified pectins to acidic liquid system. The enzymatically blocked-deesterified pectin preferably has a calcium sensitivity greater than about 200 cP or a calcium fraction greater than 20, and a xcex94 degree of esterification from about 5 to 25%.
The process for suspending particles of the present invention further comprises adding calcium ions to the acidic liquid system. The amount of calcium ions is preferably from about 10 ppm to about 2000 ppm, more preferably from about 50 ppm to about 1000 ppm, and most preferably from about 200 ppm to about 600 ppm.
The acidic liquid system can comprise proteins selected from at least one of soy, whey, and casein.
The process for suspending insoluble components of the present invention can further comprise adding a food, cosmetic, or pharmaceutical product to the acidic liquid system.
Furthermore, the present invention relates to stabilized aqueous systems containing (a) at least one enzymatically blocked-deesterified pectin that displays pseudoplasticity and substantially no phase separation in an aqueous solution comprising at least one polyvalent cation; and (b) at least one acidic liquid solution. The stabilized system can further comprise adding calcium ions to the acidic liquid solution. The amount of calcium ions is preferably from about 10 ppm to about 2000 ppm, and more preferably from about 50 ppm to about 600 ppm.
The acidic liquid solution of the stabilized system comprises proteins selected from at least one of soy, whey, and casein. The acid liquid solution can further comprise a food, cosmetic, or pharmaceutical product to the acidic liquid solution. The food product comprises at least one of fruit and vegetable. The acidic liquid solution can also comprise calcium ions.
Accordingly, it would be desirable to be able to provide a pectin for use in suspending insoluble components in acidic liquid systems that: (1) has shear thinning properties; (2) has shear thinning properties with acceptable mouth-feel; (3) cannot undergo syneresis upon storage or form a separate gel phase in the presence of relatively high levels of calcium; and (4) minimal changes in rheology during long term storage; (5) be effective at low use levels.
The present invention is directed to enzymatically blocked-deesterified pectin that displays pseudoplasticity and substantially no phase separation in an aqueous solution comprising at least one polyvalent cation at low use levels.
Pseudoplasticity is a theological behavior most desired for stabilization of particles in aqueous solution. An aqueous solution is characterized as being pseudoplastic if it displays decreasing viscosity with increasing shear rate. This is also referred too as xe2x80x9cshear thinning.xe2x80x9d This behavior is thought to be due to the formation a network structure caused by entanglement of the long chain molecules in solution. Pseudoplastic behavior of pectin is closely related to the relative size of the pectin molecules in solution. Higher molecular weight pectins exhibit this behavior at lower pectin concentrations. One approach toward increasing apparent molecular size is to introduce calcium reactive sites to the high methoxyl pectin molecule by acid deesterification and to add calcium to the solution that forms cross-links between pectin molecules. However, this leads to the formation of gel particles and syneresis and these pectins typically also exhibit thixotropic behavior in solution when calcium is present.
The calcium reactive pectins of this invention have a unique property of pseudoplastic behavior at very low pectin concentrations without gel-contraction or syneresis and are non-thixotropic. In addition, these properties are maintained upon storage at room temperature under acidic conditions.
xe2x80x9cPhase separationxe2x80x9d refers to the formation of a clear liquid above a suspended bed of particles, often with a clear boundary line. Phase separation could also be referred to as particle sedimentation for the aqueous system containing the pectin of the present invention. Severe phase separation is characterized by clear liquid surrounding the particle bed on the sides as well as the bottom. Phase separation can include, but is not limited to, particle sedimentation and/or gel contraction. xe2x80x9cSyneresisxe2x80x9d is another term, often used with firm gels and not fluid gels, which is essentially the same as gel contraction, and is yet another representation of phase separation. The test for determining phase separation is described below in the example section labeled xe2x80x9cDetermination of Particle Sedimentationxe2x80x9d, which is used to determine phase separation for particle sedimentation.
xe2x80x9cSubstantially no phase separationxe2x80x9d refers to less than 10% of phase separation in the cationic aqueous solution containing the enzymatically blocked-deesterified pectin of the present invention. The phase separation of the enzymatically blocked-deesterified pectin of the present invention is preferably at most about 10%, more preferably at most about 7%, even more preferably about 5%, and at most about 3%.
The enzymatically blocked-deesterified pectin of the present invention is also non-thixotropic in aqueous solutions when reacted with a polyvalent cation. That is, the enzymatically blocked-deesterified pectin of the present invention aids the aqueous solutions to rebuild viscosity or recover very quickly when shear is removed. The rebuild in viscosity after shear is applied is essentially identical to the value for the viscosity before shear is introduced.
In addition, although the enzymatically blocked-deesterified pectin of the present invention does not substantially display phase separation in an aqueous solution comprising at least one polyvalent cation, it does react with polyvalent cations to form molecules of larger apparent molecular size that aids in entanglement for pseudoplasticity at low pectin concentrations. Examples of polyvalent cations preferably include, but are not limited to, aluminum ions, iron ions, manganese ions, calcium ions, and magnesium ions, more preferably calcium ions and magnesium ions, and most preferably calcium ions.
The amount of the polyvalent cation present in the aqueous solution is preferably in the amount of about 10 ppm to about 2,000 ppm, and more preferably about 50 ppm to about 1,000 ppm.
The amount of the calcium ions present in the aqueous solution is preferably in the amount of about 10 ppm to about 2,000 ppm, more preferably about 50 ppm to about 1,000 ppm, and most preferably about 200 ppm to about 600 ppm.
The enzymatically blocked-deesterified pectin of the present invention preferably has a calcium sensitivity (CS) greater than about 200 centipoise (cP) or a calcium fraction (CF) greater than 20, and a xcex94 degree of esterification (xcex94DE) from about 5 to 25%. More preferably, the enzymatically blocked-deesterified pectin has a calcium sensitivity greater than about 200 cP or a calcium sensitive pectin fraction greater than 20, and a xcex94 degree of esterification from about 7 to 25%. Most preferably, the enzymatically blocked-deesterified pectin has a calcium sensitivity greater than about 200 cP or a calcium sensitive pectin fraction greater than 20, and a xcex94 degree of esterification from about 8 to 15%.
xe2x80x9cCalcium sensitivity (CS)xe2x80x9d refers to the property of a pectin product related to an increase in the viscosity of a solution of the pectin product under appropriate conditions. xe2x80x9cCalcium fraction (CF)xe2x80x9d refers to a ratio of calcium sensitivities. Methods for determination of CS and CF are described in the Analytical Procedures in the Example Section below.
As discussed above, the term xe2x80x9cdegree of esterificationxe2x80x9d is intended to mean the extent to which free carboxylic acid groups contained in the polygalacturonic acid chain of the pectin have been esterified (e.g., by methylation) or in other ways rendered non-acidic (e.g., by amidation). xe2x80x9cA degree of esterification (xcex94DE)xe2x80x9d refers to the difference in the DE between the pectins before enzymatic deesterification as compared to the pectin after enzymatic deesterification. See methods for determination of DE and xcex94DE.
In one embodiment of the present invention, the enzymatically blocked-deesterified pectin of the present invention is prepared from a high methoxyl pectin starting material with at least one enzyme. The enzyme may be present upon purification of the pectin, but other embodiments include removal, inctivation or the use of immobilized enzymes. A most preferred embodiment involves the inactivation of the enzyme before precipitation in alcohol.
xe2x80x9cPectin starting materialxe2x80x9d is intended to mean a pectin product obtained by separation of pectin from a plant material. The pectin starting material can preferably be obtained from citrus peels, apple juices, apple ciders, apple pomade, sugar beets, sunflower heads, vegetables or waste products from plants such as apples, sugar beet, sunflower and citrus fruits, more preferably apples, sugar beets and citrus plants, and most preferably citrus plants such as limes, lemons, grapefruits, and oranges.
The pectin starting material can, for example, be the acid pectin extract after purification or it could be wet pectin cake obtained after treating the acid pectin solution with alcohol. Further, the pectin starting material can, for example, be the dried or partly dried pectin in the pectin cake from precipitation, or it could be the dried, milled pectin powder as normally produced by pectin manufacturers.
As indicated above, the process in accordance with the present invention comprises deesterifying the pectin starting material with at least one enzyme to produce enzymatically blocked-deesterified pectin. The pectin starting material of the present invention preferably has a degree of esterification greater than about 60%, more preferably greater than about 65%, and most preferably greater than about 67%.
In one embodiment of the present invention, if the degree of esterification of the isolated high methoxyl pectin is preferably from about 68 to 72%, then the degree of esterification of the enzymatically blocked-deesterified pectin is preferably from about 45 to 65%, more preferably from about 50 to 62%, and most preferably from about 55 to 59%.
In another embodiment of the present invention, the degree of esterification of the high DE pectin starting material is preferably from about 5 to 25% higher than the enzymatically blocked-deesterified pectin, more preferably from about 5 to 15% higher than the enzymatically blocked-deesterified pectin, and most preferably from about 8 to 15% higher than the enzymatically blocked-deesterified pectin.
The isolated high methoxyl pectin prepared as above is then subjected to a mild controlled deesterifying treatment using a pectin deesterifying enzyme such as pectin methyl esterase isolated from plant materials or organisms capable of producing such enzymes. Examples include but are not limited to the crude enzymes that can contain pectin methyl esterase such as papain, ficin or bromelain. These pectin methyl esterase enzymes deesterify pectins to form blocks of free carboxyl groups.
In one embodiment, a 1 to 2% aqueous solution of the isolated high methoxyl pectin is prepared from dry high DE pectin using appropriate heat and agitation to ensure complete dissolution of the pectin. Then sufficient sodium chloride is added to the preparation to achieve a 1% w/v concentration of sodium chloride based on the original volume of water used in the preparation of the pectin solution. Sodium chloride is known to enhance the activity of pectin deesterifying enzymes. The temperature of this solution is then adjusted to between 20 to 50xc2x0 C. depending upon the temperature optimum of the deesterifying enzyme used. The pH of the solution is then adjusted to about 5 to 8 using 0.5 M sodium hydroxide (NaOH). Finally, an appropriate amount of the pectin deesterifying enzyme is added to the pectin solution such as any of those produced by the methods described above in order to achieve controlled deesterification.
In the present invention, the ester groups on the pectin are removed in a sequential fashion, preferably by a deesterifying enzyme. Deesterifying enzymes or pectin methyl esterases are pectin enzymes that deesterify pectin to produce free carboxyl groups and free methanol. Deesterifying enzymes in the preferred embodiment deesterify pectins in blockwise manner (sequential fashion). xe2x80x9cBlockwisexe2x80x9d or xe2x80x9csequentialxe2x80x9d deesterification occurs when deesterifying enzymes attack pectins either at non-reducing ends or next to free carboxyl groups and then proceed along the pectin molecules by a single-chain mechanism, thereby creating blocks of unesterified galacturonic acid units.
The pectin methyl esterase is extracted from plant tissues selected from, but not limited to, at least one of apples, apricots, avocados, bananas, berries, figs, limes, grapefruits, mandarins, cherries, currants, grapes, mangos, papayas, passion fruits, peaches, pears, pineapple, plums, beans, carrots, cauliflowers, cucumbers, leeks, onions, peas, potatoes, radishes and tomatoes. The enzyme may also be a mixture of more than one pectin methyl esterase from different sources or may also contain other enzymes that act on pectin.
In one preferred embodiment, the enzyme is extracted from papayas. More preferably the enzyme is papain. Most preferably, the enzyme is Colipulin(copyright)Liquid product code 5045 manufactured by Gist-Brocades International B.V., Charlotte, N.C. 28224.
The pH of the reaction solution is maintained at about 7 by continuous addition of 0.5 M NaOH. The up-take of NaOH by the solution is used to monitor the progress of the deesterification reaction. Once the deesterification has proceeded to the required degree to produce a pectin in accordance with the invention, the reaction is terminated by the addition of acid to reduce the pH of the solution to 4 or less. The reaction mixture is then heated to approximately 75xc2x0 C. for 15 minutes to deactivate the enzyme followed by cooling of the mixture. The enzyme treated pectin can then be recovered from the solution by adding an equal volume of 60-80% IPA. The insoluble pectin is collected, pressed and washed with additional volumes of IPA and finally pressed to 30-50% by weight of dry matter.
The enzymatically block-deesterified pectin can further be dried and milled to small particles. Drying of the pectin can be accomplished by any technique in the art (e.g., atmospheric or reduced-pressure ovens) to a moisture content of less than about 50%, preferably less than about 25%. The drying temperature should be maintained below the temperature at which the pectin starts to lose its properties, e.g., color, molecular weight, etc. Any milling technique in the art can be used to mill the pectin product to the desired particle size. It is most preferred that the final product be in dry, powder form, with a moisture content of about 12 wt. % or less. xe2x80x9cDry powder formxe2x80x9d is intended to mean that the product be pourable without substantial caking. The preferred final product is in the form of a powder for ease of use.
The process for preparing the deesterified pectin of the present invention can be prepared in a continuous process or a single batch, preferably in a continuous process. In accordance with the present invention, the enzymatically blocked-deesterified pectin can be used in a process for suspending insoluble components in an acidic liquid system. The process includes adding the deesterified pectin that has been deesterified in a sequential pattern to an acidic liquid system.
xe2x80x9cInsoluble componentsxe2x80x9d refer to any insoluble particulates such as pulps, essential oils, coloring agents such as natural or otherwise, minerals, botanicals, and pharmaceuticals that have the tendency to phase separate in one or more places in a solution via sedimentation, creaming or other such destabilization mechanisms. The test for phase separation in the context of the present invention is described below in the example section labeled xe2x80x9cDetermination of Particle Sedimentationxe2x80x9d which is a test for phase separation for particle sedimentation.
xe2x80x9cAcidic liquid system or acidic aqueous systemxe2x80x9d herein refers to acidic food, cosmetic, and pharmaceutical products in liquid form which contain a suitable concentration of polyvalent cations or to which polyvalent cations can be added. Examples of liquid food products preferably include, but are not limited to, drinks containing fruits, vegetables, or mixtures thereof, soups, salad dressings, and sauces. The acidic drink can be non-carbonate or carbonate, consumed undiluted or diluted, sweetened or unsweetened, salted or unsalted, with or without alcohol, or combinations thereof.
Examples of liquid acidic cosmetic products include, but are not limited to, perfumes, sun tan lotions, sun screen lotions, body lotions, deodorants, antiperspirants, conditioners and shampoos. Examples of liquid acidic pharmaceutical products include, but are not limited to, cough syrups, liquid forms of headache medicines, liquid forms of decongestants, and liquid forms of anti-inflammatory medicines.
The pH of the acidic liquid system in the process of the present invention is from about 2.0 to about 5, preferably from about 2.5 to about 4.5, and more preferably from about 3 to about 4.
The acidic liquid system can have a solid content from about 0. 1% to about 50% by weight, preferably from about 1 to about 30% by weight, and more preferably from about 5 to about 20% by weight.
In one embodiment of the present invention, the acidic liquid system is a beverage drink that can have a solid content from about 0.1% to about 50% by weight, an alcohol content of between from about 0% to about 5% by volume, a salt (NaCl) content of about 0% to 3%, and a sugar content of from about 0.1% to about 15%.
The weight ratio, of the enzymatically blocked-deesterified pectin to the acidic liquid system in the process of the present invention, can be from about 0.0001 to about 0.03, preferably from about 0.0005 to about 0.006, and more preferably from about 0.0015 to about 0.035.
The total amount, of enzymatically blocked-deesterified pectin in the acidic liquid system, can be from about 0.15% to about 0.35% by dry weight, preferably from about 0.05% to about 0.6% by dry weight, and more preferably from about 0. 1% to 0.3% by dry weight.
The aqueous system must also contain calcium ions or other polyvalent cations and thus the addition of calcium ions is not optional unless calcium is already present from another ingredient such as a calcium-fortifying agent.
Calcium ions react with the pectin as described in this invention to form a weak gel network of very low but stable viscosity that is pseudoplastic, non-thixotropic and stable at low concentrations. In addition this calcium-pectin solution shows no signs of syneresis. These properties are of particular value to the manufacturer who is seeking to fortify beverages and pharmaceutical products with calcium for nutritional purposes. Calcium levels of about 1000 ppm (i.e., micrograms calcium ion per gram of acidic liquid food) can be achieved without adverse affects on the ability to stabilize particles. This level of calcium addition to a 12 fluid ounce beverage represents a significant amount of the RDA (Recommended Daily Allowance) for calcium for an adult as recommended by the FDA (Food and Drug Administration).
The xe2x80x9cstable viscosityxe2x80x9d or xe2x80x9cstabilityxe2x80x9d that calcium ions provide to the acidic liquid system refers to the maintenance of insoluble components in suspension and the homogeneity of the suspension initially formed. Stability also means that the rheology of the acidic liquid system is stable for a time period of at least one to twelve months or longer.
Calcium ions used in the process of the present invention can be in a solid salt form or solution. Examples of calcium salts include, but are not limited to, calcium chloride, calcium acetate, calcium propionate, calcium oxide, calcium carbonate, calcium citrate, calcium lactate, calcium malonate, calcium gluconate, and, preferably calcium chloride, calcium acetate, calcium propionate, calcium oxide, calcium carbonate, calcium citrate, calcium lactate, calcium malonate, and calcium gluconate, more preferably calcium citrate, calcium lactate, calcium malonate, and calcium gluconate.
The amount of calcium ions in the system can be from about 0.001% to about 0.2% (10 to 2000ppm), preferably from about 0.005% to about 0.1% (50 to 1000 ppm), and more preferably from about 0.02% to about 0.06% (200 to 600 ppm).
The weight ratio of the calcium ions to the enzymatically blocked-deesterified pectin of the present invention can be from about 0.001 to about 10, preferably from about 0.01 to about 1.0, and more preferably from about 0.03 to about 0.30.
The weight ratio of the enzymatically blocked-deesterified pectin, acidic liquid system, and food, cosmetic, or pharmaceutical product in the process of the present invention can be from about 0.0001 to about 0.03, preferably from about 0.0005 to about 0.006, and more preferably from about 0.0015 to about to about 0.035.
When the enzymatically blocked-deesterified pectin of the present invention is added to an acidic liquid, it provides minimal changes in rheology during long term storage. In addition, the pectin of the present invention has shear thinning properties with acceptable mouth-feel. The deesterified pectin of the present invention does not undergo syneresis (form phase separation) upon storage or form a separate gel phase in the presence of relatively high levels of calcium.
The amount of the enzymatically blocked-deesterified pectin in the system of the present invention is from about 0.01% to about 3% by dry weight, preferably from about 0.05 to about 0.6%, and more preferably from about 0.10 to about 0.4%.
Examples of the acidic liquid of the present invention include, but are not limited to, ethanol and water, glycerol and water, and propylene glycol and water. Also in accordance with the present invention, the enzymatically blocked-deesterified pectin can be used in a stabilized acidic liquid system. The stabilized acidic liquid system of the present invention includes an enzymatically blocked-deesterified pectin and an acidic aqueous solution.
xe2x80x9cAcidic liquidxe2x80x9d herein refers to acidic food, cosmetic, and pharmaceutical products in aqueous form. Examples of liquid food products preferably include, but are not limited to, drinks containing fruits, vegetables, or mixtures thereof, soups, salad dressings and sauces. The acidic drinks can be non-carbonated or carbonate, consumed undiluted or diluted, sweetened or unsweetened, salted or unsalted, with or without alcohol, or combinations thereof.
Examples of liquid acidic cosmetic products include, but are not limited to, perfumes, sun tan lotions, sun screen lotions, body lotions, deodorants, antiperspirants, conditioners and shampoos. Examples of liquid acidic pharmaceutical products include, but are not limited to, cough syrups, liquid forms of headache medicines, liquid forms of decongestants, and liquid forms of anti-inflammatory medicines.
The pH of the acidic aqueous solution of the present invention is from about 2.0 to about 5, preferably from about 2.5 to about 4.5, and more preferably from about 3 to about 4.
The acidic aqueous solution can have a content from about 0.1% to about 50% by volume, preferably from about 1 to about 30% by volume, and more preferably from about 4 to about 18% by volume.
The acidic aqueous solution in the stabilized acidic liquid system is from about 2.5 to about 5, preferably from about 2.8 to about 4.5, and more preferably from about 3 to about 5.
In addition, the system can further include a food, cosmetic or pharmaceutical product. Alternatively, the system can further include (1) calcium ions and (2) a food, cosmetic or pharmaceutical product.
The weight ratio of the enzymatically deesterified pectin and the calcium ions in the stabilized acidic liquid system is from about 0.001 to about 0.2, preferably from about 0.005 to about 0.01, and more preferably from about 0.02 to about 0.06.
Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent.
The following preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.